Concrete pavers are high strength modular concrete units that fit together to create paved areas. Concrete pavers have been used for many years to construct paved areas for pedestrian and vehicular traffic. Concrete pavers have been used to pave walkways, driveways, streets, airport taxiways, parking lots, patios, and the like.
Many pavers are made with spacers on their sides to maintain a uniform spacing between the pavers. The spacers are designed to maintain a minimum joint width between the pavers that provides just enough space for sand to effectively fill the joints between the pavers. The sand between the pavers transfers shear loads between the pavers, thereby achieving vertical interlock of the pavers to prevent vertical movement of the pavers relative to one another. A common joint width for these types of pavers is about 1.5 mm.
The water permeability of the pavement can be increased, when desirable, by increasing the joint width. The Interlocking Concrete Pavement Institute, Tech Spec Number 1, May 2001 Revision (the “ICPI Tech Spec”), suggests that permeable pavement have joint widths of about 10 mm to about 30 mm. Accordingly, concrete pavers have been made with suitable spacer dimensions of this magnitude to create highly water permeable pavements.
In addition to water permeability, factors to be considered when installing pavers are the anticipated loading on the pavers and the aesthetics sought by the customer. Concrete pavers can be laid in a number of patterns to meet differing engineering requirements and aesthetic requirements. A popular pattern from both an aesthetic and engineering standpoint is a herringbone pattern. A herringbone pattern is visually appealing, and is the most effective pattern for dispersing forces from braking and accelerating vehicles, thereby maintaining horizontal interlock between the pavers. Herringbone patterns are usually installed with the lengths of the pavers at 45 degrees with respect to the anticipated direction of pedestrian or vehicular traffic, or they are laid in a 90 degree pattern as shown in FIG. 1.
Pavers are increasingly being installed using mechanical installation. In mechanical installation, machinery is used to lift and place layers of pavers that are prearranged in their final laying pattern. Mechanical installation increases the rate of paving, reduces worker fatigue, and reduces the risk of injury to workers.